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<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="boost_regex.unicode"></a><a class="link" href="unicode.html" title="Unicode and Boost.Regex">Unicode and Boost.Regex</a>
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<p>
      There are two ways to use Boost.Regex with Unicode strings:
    </p>
<h5>
<a name="boost_regex.unicode.h0"></a>
      <span class="phrase"><a name="boost_regex.unicode.rely_on_wchar_t"></a></span><a class="link" href="unicode.html#boost_regex.unicode.rely_on_wchar_t">Rely
      on wchar_t</a>
    </h5>
<p>
      If your platform's <code class="computeroutput"><span class="keyword">wchar_t</span></code> type
      can hold Unicode strings, and your platform's C/C++ runtime correctly handles
      wide character constants (when passed to <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">iswspace</span></code>
      <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">iswlower</span></code> etc), then you can use <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">wregex</span></code>
      to process Unicode. However, there are several disadvantages to this approach:
    </p>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
          It's not portable: there's no guarantee on the width of <code class="computeroutput"><span class="keyword">wchar_t</span></code>,
          or even whether the runtime treats wide characters as Unicode at all, most
          Windows compilers do so, but many Unix systems do not.
        </li>
<li class="listitem">
          There's no support for Unicode-specific character classes: <code class="computeroutput"><span class="special">[[:</span><span class="identifier">Nd</span><span class="special">:]]</span></code>, <code class="computeroutput"><span class="special">[[:</span><span class="identifier">Po</span><span class="special">:]]</span></code>
          etc.
        </li>
<li class="listitem">
          You can only search strings that are encoded as sequences of wide characters,
          it is not possible to search UTF-8, or even UTF-16 on many platforms.
        </li>
</ul></div>
<h5>
<a name="boost_regex.unicode.h1"></a>
      <span class="phrase"><a name="boost_regex.unicode.use_a_unicode_aware_regular_expr"></a></span><a class="link" href="unicode.html#boost_regex.unicode.use_a_unicode_aware_regular_expr">Use
      a Unicode Aware Regular Expression Type.</a>
    </h5>
<p>
      If you have the <a href="http://www.ibm.com/software/globalization/icu/" target="_top">ICU
      library</a>, then Boost.Regex provides a distinct regular expression type
      (boost::u32regex), that supports both Unicode specific character properties,
      and the searching of text that is encoded in either UTF-8, UTF-16, or UTF-32.
      See: <a class="link" href="ref/non_std_strings/icu.html" title="Working With Unicode and ICU String Types">ICU string class support</a>.
    </p>
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<td align="right"><div class="copyright-footer">Copyright © 1998-2013 John Maddock<p>
        Distributed under the Boost Software License, Version 1.0. (See accompanying
        file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
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